|can i plant this hibiscus - sinensis outside in oklahoma and leave it all winter?
|No, this is a tropical plant and it will die if allowed to freeze. You need to bring it indoors before the temperatures drop below 45 degrees in the fall or it will be damaged by the cold. If you want to keep it as a flowering houseplant you will need to bring it indoors sooner than that. If you want a hardy flowering hibiscus shrub you would need to plant the Hibiscus syriacus or rose of sharon.